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Melatonin (MT) participates in plants' responses in plants’ response to cadmium (Cd) tolerance, although its work model remains elusive. Here, the function of MT in adjusting Cd accumulation in Gossypium hirsutum (CCRI12) was investigated. In this research we observed that exogenous 50 μM MT significantly reduced the Cd accumulation under 100 μМ Cd stress for 7 days of treatment in cotton seedlings. Cd markedly induced the ROS (H2O2, O2-) accumulation and elevated the expression of transporters for Cd uptake and translocation. After application of MT reduced ROS and MDA accumulation in response to high induction of antioxidant defense system; the genes encoding superoxide dismutase (GhSOD), catalase (GhCAT), and peroxidase (GhPOD), ascorbate peroxidase (GhAPX), and glutathione S-transferase (GhGST) were significantly upregulated accompanied by their level of content. Furthermore, MT down-regulated transporters for Cd uptake include Natural Resistance-Associated Macrophage Protein 1 (GhNRAMP3), Zinc/Iron-regulated transporter-like protein (GhZIP1/4/6), Heavy Metal ATPase gene (GhHMA2), and ATP-binding Cassette sub family C (GhABCC3/2). Exogenous application of MT raised the hemicelluloses, cellulose and pectin content accompanied by their expression levels, xyloglucan endotransglucosylase/hydrolase (GhXTH28/6/9/B), cellulose synthase like (GhCSLG1/2) and COBRA-like (GhCOBL4), pectin acetylesterases (GhPAE8/7), pectin methylesterases (GhPME31) which in turn increased the cell wall's binding capacity to Cd.

The pigment gland is a morphological characteristic of Gossypium and its related genera. Gossypium bickii (G1) is characterized by delayed pigment gland morphogenesis in the cotyledons. In this study, a reference-grade genome of G1 was generated, and comparative genomics analysis showed that G1 was closest to Gossypium australe (G2), followed by A- and D-genome species. Two large fragment translocations in chromosomes 5 and 13 were detected between the G genome and other Gossypium genomes and were unique to the G1 and G2 genomes. Compared with the G2 genome, two large fragment inversions in chromosomes 12 and 13 were detected in G1. According to the phylogeny, divergence time, and similarity analysis of nuclear and chloroplast genomes, G1 was formed by hybridization between Gossypium sturtianum (C1) and a common ancestor of G2 and Gossypium nelsonii (G3). The coordinated expression patterns of pigment gland formation (GoPGF) and gossypol biosynthesis genes in G1 were verified to be consistent with its phenotype, and nine genes that were related to the process of pigment gland formation were identified. A novel gene, GbiCYP76B6, regulated by GoPGF, was found to affect gossypol biosynthesis. These findings offer insights into the origin and evolution of G1 and its mechanism of pigment gland formation and gossypol biosynthesis.

Hepatitis is an inflammatory disease of the liver and is considered one of the leading causes of death worldwide. Due to its scavenging activity, Punica granatum may be used for the treatment and prevention of liver diseases. The current study investigated the protective mechanism underlying the effects of pomegranate against a rat model of carbon tetrachloride–induced liver injury. Intraperitoneal injection of CCl4 resulted in liver inflammation, oxidative stress, and accumulation of lipid in hepatocytes. CCl4 induced a downregulation of superoxide dismutase (SOD), glutathione (GSH), and melonaldehyde (MDA). Pomegranate protection was assessed in terms of biochemical parameters, histopathology, and immunohistochemistry. Promegranate administration decreased inflammation, elevated serum enzymes and ROS production, and countered the debilitating effects caused by CCl4. In addition, CCl4-induced histological changes were absent in the crude pomegranate extract group, which also enhanced the scavenging activity of reactive oxygen species by enhancing the antioxidant defense mechanism as confirmed by detecting MDA, SOD, and GSH expressions. The migration of CD68+ macrophages was halted at the injured area of the central vein and the number of macrophages was reduced to the normal control by the crude extract compared to the positive control silymarin group. Likewise, protective effects of ethylacetate and the aqueous fraction of the crude extract were also observed. However, the butanol and n-hexane fractions displayed increased levels of ALT, AST, and ALP as compared to silymarin. About 25% damage to hepatocytes was observed in the butanol and n-hexane group by histopathological examination, which is a little better compared to the CCl4-treated group. The crude extract and its ethyl acetate and aqueous fractions may be accountable for the hepatoprotective potential of Punica granatum, which was further confirmed by in vivo experiments. Together, these findings confirm that pomegranate exerts hepatoprotective activity against CCl4-induced oxidative stress and liver damage.

Heavy metals-based changes in the plants and their alleviation through eco-friendly agents including reduced glutathione (GSH) have been widely studied. In the present experiment, we tested the alleviatory role of reduced glutathione (GSH) in seedlings of upland cotton cultivar, TM-1 under lead (Pb) toxicity. Plants were grown in the Hoagland solution containing Pb (0 μM), Pb (500 μM), GSH (50 μM), and GSH + Pb (50 μM + 500 μM). Lead exposure exacerbated hydrogen peroxide (H2O2) and hydroxyl radical (OH•) levels, induced lipid peroxidation (MDA), and decreased the activities of catalase (CAT) and ascorbate peroxidase (APX) in the terminal and median leaves of 28-days old cotton seedlings stressed for 10 days. However, in the primary and secondary roots, CAT activity was increased but APX decreased. Similarly, peroxidase (POD) and superoxide dismutase (SOD) activities were enhanced in the median leaves but a declining trend was observed in the terminal leaves, primary roots and secondary roots. Glutathione reductase (GR) activity, ascorbic acid (AsA) contents and GSH concentrations were increased in all parts except AsA in the median leaves. Transmission electron micrographs of Pb-treated plants exhibited deformed cell wall and cell membrane, disfigured chloroplasts and irregularly shaped mitochondria in the terminal and median leaves. Further, cell membrane, mitochondria, nucleus and other cell organelles in root cells were severely affected by the Pb. Thus their identification was little bit difficult through ultramicroscopy. External GSH stabilized leaf and root ultramorphology by stabilizing cell membranes, stimulating formation of multivesicular body vesicles, and by maintaining structural integrity of other organelles. Evidently, GSH played major alleviatory role against Pb toxicity in upland cotton.

The growing demand for environmentally friendly semiconductors that can be tailored and developed easily is compelling researchers and technologists to design inherently bio-compatible, self-assembling nanostructures with tunable semiconducting characteristics. Peptide-based bioinspired materials exhibit a variety of supramolecular morphologies and have the potential to function as organic semiconductors. Such biologically or naturally derived peptides with intrinsic semiconducting characteristics create new opportunities for sustainable biomolecule-based optoelectronics devices. Affably, halide perovskite nanocrystals are emerging as potentially attractive nano-electronic analogs, in this vein creating synergies and probing peptide-perovskite-based bio-electronics are of paramount interest. The physical properties and inherent aromatic short-peptide assemblies that can stabilize, and passivate the defects at surfaces assist in improving the charge transport in halide perovskite devices. This review sheds light on how these peptide-perovskite nano-assemblies can be developed for optical sensing, optoelectronics, and imaging for biomedical and healthcare applications. The charge transfer mechanism in peptides along with as an outlook the electron transfer mechanism between perovskite and short peptide chains, which is paramount to facilitate their entry into molecular electronics is discussed. Future aspects, prevailing challenges, and research directions in the field of perovskite-peptides are also presented., (© 2024 The Author(s). Advanced Science published by Wiley‐VCH GmbH.)

Unraveling the knowledge of the complex refractive index and photophysical properties of the perovskite layer is paramount to uncovering the physical process that occurs in a perovskite solar cell under illumination. Herein, we probed the optical and photophysical properties of FAPbI 3 (FAPI) and Cs 0.1 FA 0.9 PbI 3 (CsFAPI) thin films deposited from pre-synthesized powder, by the spectroscopic ellipsometer and time-resolved fluorescence spectra. We determined the complex refractive index of perovskite films by fitting the measured spectroscopic ellipsometer data with the three-oscillator Tauc-Lorentz (T-L) model. We deduced that the CsFAPI thin film had a slightly lower absorption coefficient than the FAPI, but a higher refractive index and dielectric constant than the FAPI. The peak photoluminescence (PL) emission of FAPI and CsFAPI thin film on glass substrates was observed around 803 nm and 799 nm, respectively, while on ITO substrates, both FAPI and CsFAPI thin film was quenched and red-shifted to 816 nm. The methylammonium free pure CsFAPI-based perovskite solar cell fabricated in p-i-n configuration, measured a competitive efficiency of 16.14%, characterized by a J SC of 23.995 mA cm -2 , V OC of 912 mV, and FF of 73.74%., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Research efforts in various multitudes have been demonstrated to stabilize methylammonium (MA)- and bromide (Br)-free formamidinium lead triiodide (FAPI) perovskite thin films. Despite these commendable efforts, pure FAPI perovskite thin film is prone to critical phase-transition issues due to its thermodynamically stable non-perovskite phase (2H). Here, in this work, we propose a rational additivization strategy to overcome this challenge. Our multifunctional ammonium salt containing a sulfur heteroatom shifts the thermodynamic stability from the 2H phase to an intermediate phase closer to the cubic phase. Along with the high crystallinity, micron-sized grains with preferred (00h) facet orientation stem the Pb … S interaction to offer exceptional stability against high relative humidity, direct water incursion, and shelf-life aging. Our findings through experimental and theoretical studies substantiate the role of Pb … S interaction in stabilizing the perovskite cubic phase and the stoichiometric distribution of elemental components., Competing Interests: The authors declare no competing interests., (© 2023 The Author(s).)

To solve the toxicity issues related to lead-based halide perovskite solar cells, the lead-free double halide perovskite Cs 2 AgBiBr 6 is proposed. However, reduced rate of charge transfer in double perovskites affects optoelectronic performance. We designed a series of pyridine-based small molecules with four different arms attached to the pyridine core as hole-selective materials by using interface engineering. We quantified how arm modulation affects the structure-property-device performance relationship. Electrical, structural, and spectroscopic investigations show that the N 3 , N 3 , N -carbazole-3,6-diamine arm's robust association with the pyridine core results in an efficient hole extraction for 6 , N 6 -tetrakis(4-methoxyphenyl)-9 H -carbazole-3,6-diamine arm's robust association with the pyridine core results in an efficient hole extraction for PyDAnCBZ due to higher spin density close to the pyridine core. The solar cells fabricated using Cs 2 AgBiBr 6 as a light harvester and PyDAnCBZ as the hole selective layer measured an unprecedented 2.9% power conversion efficiency. Our computed road map suggests achieving ∼5% efficiency through fine-tuning of Cs 2 AgBiBr 6 . Our findings reveal the principles for designing small molecules for electro-optical applications as well as a synergistic route to develop inorganic lead-free perovskite materials for solar applications., Competing Interests: The authors declare no competing financial interest., (© 2023 The Authors. Published by American Chemical Society.)

Lead halide perovskites are attractive pigments to fabricate solar cells in the laboratory, owing to their high power conversion efficiency. However, given the presence of Pb, such materials also have a high level of toxicity and are carcinogenic for humans and aquatic life. Arguably, this hampers their acceptability for immediate commercialization. This study entails the synthesis, optoelectronic properties, and photovoltaic parameters of two-dimensional copper-based perovskites as an environmentally benign alternative to lead-based perovskites. The perovskites - (CH 3 NH 3 ) 2 CuCl 4-x Br x with x=0.3 and 0.66 - are derivatives of the stable (CH 3 NH 3 ) 2 CuCl 4 . The single crystals and powders diffractograms suggest compositions with variations in Cl/Br ratio and dissimilar bromine localization in the inorganic framework. The copper mixed halide perovskite exhibits a narrow absorption with a bandgap of 2.54-2.63 eV related to the halide ratio disparity (crystal color variation). These findings demonstrate the impact of halides to optimize the stability of methylammonium copper perovskites and provide an effective pathway to design eco-friendly perovskites for optoelectronic applications., (© 2023 Wiley-VCH GmbH.)

The increasing demand for solar energy requires materials from earth-abundant elements to ensure cost-effective production. One such light harvester Cu 2 CdSn(S,Se) 4 fulfills this property. We report the development of functional solar cells based on Cu 2 CdSn(S,Se) 4 , which has been previously unreported. Furthermore, we deposited the thin films of Cu 2 CdSn(S,Se) 4 by spray pyrolysis using environmentally benign solvents, in a superstrate architecture, reducing the potential cost of upscaling, the environmental hazards, and enabling its use in semitransparent or tandem solar cells. We analyze the Cu 2 CdSn(S,Se) 4 and its optoelectronic characteristics with different sulfur and selenium ratios in the composition. We noted that Se is homogeneously distributed in the absorber and electron transport layer, forming a Cd(S,Se) phase that impacts the optoelectronic properties. The introduction of Se, up to 30%, is found to have a positive impact on the solar cell performance, largely improving the fill factor and absorption in the infrared region, while the voltage deficit is reduced. The device with a Cu 2 CdSn(S 2.8 Se 1.2 ) composition had a 3.5% solar-to-electric conversion efficiency, which is on par with the reported values for chalcogenides and the first report using Cu 2 CdSn(S,Se) 4 . We identified the critical factors that limit the efficiency, revealing pathways to further reduce the losses and improve the performance. This work provides the first proof of concept of a novel material, paving the way for developing cost-efficient solar cells based on earth-abundant materials.

Formamidinium lead iodide-based solar cells show promising device reliability. The grain imperfection can be further suppressed by developing powder methodology. The water uptake capability is critical for the stability of α-formamidinium lead triiodide (FAPbI 3 ) thin films, and elucidating the migration of hydrogen species is challenging using routine techniques such as imaging or mass spectroscopy. Here, we decipher the proton diffusion to quantify indirect monitoring of H migration by following the N-D vibration using transmission infrared spectroscopy. The technique allows a direct assessment of the perovskite degradation associated with moisture. The inclusion of Cs in FAPbI 3 , reveals significant differences in proton diffusion rates, attesting to its impact. CsFAPbI 3 's ability to block the active layer access by water molecules is five times higher than α-FAPbI 3, which is significantly higher than methylammonium lead triiodide (MAPbI 3 ). Our protocol directly probes the local environment of the material to identify its intrinsic degradation mechanisms and stability, a key requirement for optoelectronic applications., Competing Interests: The authors declare no competing interests., (© 2023 The Author(s).)

Structural and electronic imperfections are the origin of defects and lead to nonradiative recombination that is detrimental to fabricating efficient perovskite solar cells. Here, we propose a powder engineering methodology for α-FAPbI 3 as a precursor material. Our developed methodology of α-FAPbI 3 synthesis mitigates the notorious structural and electronic imperfections evidenced by a significant decline in the microstrain and Urbach energy as compared to reported δ-FAPbI 3 powder and conventional precursor routes. In addition to the performance enhancement in photovoltaics, our engineered powder showed remarkable thermal and moisture stability along with cost-effectiveness through the employment of low-grade PbI 2 . Further, through additive engineering, with the use of ultrahydrophobic perfluoroalkyl phosphate anion-based ionic liquids, the microstrain and Urbach energy achieved the lowest values of 1.67 × 10 -4 and 12.47 meV, respectively, as a result of defect passivation and a semi-ionic F-Pb interaction that stabilizes the surface.

The past decade has witnessed tremendous advancement in the field of halide perovskite (PSK) as a choice of material for high-performing solar cells fabrication. Here, we investigate the impact of the halide exchange through N-bromosuccinimide (NBS) treatment in MAPbI 3 based solar cells. We observed the partial halide exchange (I - to Br - ) or the filling of halide (X - ) vacancy upon treatment of different NBS concentrations experimentally by spectroscopic and diffractogram studies. We noted that halide exchange impacts the crystallization and is beneficial in improving the photovoltaic performance. The optimized 0.5 % NBS treated PSC exhibited a power conversion efficiency of 17.87 % due to an increment in open-circuit voltage (V oc ) and short circuit current (J sc ). We noted improved perovskite crystal growth upon Br - substitution; eventually, it helps to lower the trap density, reducing non-radiative recombination and renders the enhancement of long-term stability of PSC., (© 2022 Wiley-VCH GmbH.)

To drive the development of perovskite solar cells (PSCs), hole-transporting materials are imperative. In this context, pyridine derivatives are being probed as small molecules-based hole-transporting materials due to their Lewis base and electron-deficient unit. Herein, we focused our investigation on pyridine isomer molecules 4,4'-(10-(pyridin- x -yl)-10 H -phenothiazine-3,7-diyl)bis( N , N -bis(4-methoxyphenyl)aniline) ( x = 2 , 3 , or 4 ), in which the pyridine nitrogen heteroatom is located at the 2, 3, and 4 positions, named as 2PyPTPDAn , 3PyPTPDAn , and 4PyPTPDAn , respectively. We decipher the structure-properties-device performance relationship impacted by the different N -atom positions in pyridine. In the case of 3PyPTPDAn , the partial orbital overlap between highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) favors the generation of neutral excitons and hole transport, as well as improves the film-formation ability, and this induces efficient hole extraction as compared to their 2,4 analogues. The solar cells fabricated with 3PyPTPDAn gave on-par photovoltaic performance as that of typical Spiro-OMeTAD, and higher performance than those of 2PyPTPDAn and 4PyPTPDAn . The hydrophobicity and homogeneous film properties of 3PyPTPDAn add merits to the stability. This work emphasizes the guidelines to develop small molecules for organic solar cells, organic light-emitting diodes, and thermally activated delayed fluorescence.

Slowing the degradation of perovskite-based solar cells (PSCs) is of substantial interest. We engineered the surface by introducing a hydrophobic overlayer on a three-dimensional (3D) perovskite using fluorinated or nonfluorinated aryl ammonium cation spacers. The placement of a fluoroarene cation allows the formation of a bilayer structure, that is, layered/3D perovskites. By doing so, the surface hydrophobic character increases notably by the virtue of the perfluorinated benzene moiety. The fabricated devices thereof gave higher performance and longevity than control devices in addition to boosting reliability. The fluoro-phenethylammonium iodide (FPEAI)-based devices showed lower nonradiative carrier recombination. To decipher the orientation of the spacer cation in this bilayer structure, we probed the surface by polarization-modulated infrared reflection-absorption spectroscopy and noted substantial differences in the orientation due to the presence of fluorine substitution. We hypothesize that the stronger van der Waals interactions due to the higher electronegativity in FPEAI govern the orientation and performance enhancement and act as a barrier to moisture decomposition.

Hole-selective layers are an indispensable component for the fabrication of effective perovskite solar cells. We designed and developed two phenothiazine-based hole transport materials: PTADAnCBZ with an electron-donating sulfur atom and PTODAnCBZ with an electron-withdrawing sulfone group in the core. PTODAnCBZ in contrast to PTADAnCBZ possesses a unique molecular orbital distribution and lower dihedral angles, which endowed it with excellent optoelectrical properties, improved charge transportation, and thermal stability. The solar cells fabricated with PTODAnCBZ yielded a higher photovoltaic (PV) performance as compared to PTADAnCBZ and were on par in terms of performance with those fabricated with Spiro-OMeTAD. Notably, the phenothiazine-based PV devices showed improved stability under multi-stress conditions including moisture, moisture and light, and moisture and heat. Phenothiazine-based molecules showed unparalleled thermal stability as compared to the doped Spiro-OMeTAD. Our findings pinpoint the advantages of cost-effective phenothiazine with dioxide as hole-selective layers and suggest its application in a variety of optoelectrical devices such as PVs and organic LED.

Here, we present a protocol for the fabrication of inverted ( p-i-n )-type perovskite solar cells, unraveling its electrical merits via immittance spectroscopy. The immittance spectroscopy is a prevailing technique for both qualitative and quantitative analyses of charge carrier dynamics in working devices. This technique integrates the temperature-dependent capacitance-frequency ( C-f ) spectra, impedance spectra, and Mott-Schottky analyses. This protocol is also applicable for typical ( n-i-p ) perovskite solar cells and other multilayer semiconductor devices. For complete details on the use and execution of this protocol, please refer to Khan et al. (2019, 2021)., Competing Interests: The authors declare no competing interests., (© 2021 The Author(s).)

A library of metal oxide-conjugated polymer composites was prepared, encompassing WO 3 -polyaniline (PANI), WO 3 -poly(N-methylaniline) (PMANI), WO 3 -poly(2-fluoroaniline) (PFANI), WO 3 -polythiophene (PTh), WO 3 -polyfuran (PFu) and WO 3 -poly(3,4-ethylenedioxythiophene) (PEDOT) which were used as hole selective layers for perovskite solar cells (PSCs) fabrication. We adopted machine learning approaches to predict and compare PSCs performances with the developed WO 3 and its composites. For the evaluation of PSCs performance, a decision tree model that returns 0.9656 R 2 score is ideal for the WO 3 -PEDOT composite, while a random forest model was found to be suitable for WO 3 -PMANI, WO 3 -PFANI, and WO 3 -PFu with R 2 scores of 0.9976, 0.9968, and 0.9772 respectively. In the case of WO 3 , WO 3 -PANI, and WO 3 -PTh, a K-Nearest Neighbors model was found suitable with R 2 scores of 0.9975, 0.9916, and 0.9969 respectively. Machine learning can be a pioneering prediction model for the PSCs performance and its validation., (© 2021 Wiley-VCH GmbH.)

The current decade has witnessed a surge of progress in the investigation of methyl ammonium lead iodide (MAPbI3) perovskites for solar cell fabrication due to their intriguing electro-optical properties, despite the intrinsic degradation of the material that has restricted its commercialisation. As a promising alternative, solar cells based on its formamidinium analogue, FAPbI3, are currently being actively pursued for having demonstrated a certified efficiency of 24.4%, while the room-temperature conversion to a non-perovskite δ-phase impedes its further commercialisation, and strategies have been adopted to overcome this phase instability. An in-depth and real-time understanding of microstructural relationships with optoelectronic properties and their underlying mechanisms using operando in situ spectroscopic techniques is paramount. Thus, the design and development of a new process, data driven methodology, characterization and evaluation protocols for perovskite absorber layers and the fabricated devices is a judicious research direction. Here, in this perspective, we shed light on the compositional, surface engineering and crystallization kinetics manipulations for FAPbI3, followed by a proposition for unified testing protocols, for scalling of devices from the lab to the market.

The overproduction of reactive oxygen species during abiotic stress in plants causes oxidative stress that damage the cell normal functions. For reactive oxygen species (ROS) scavenging, plants developed a defense system with antioxidant enzymes. To measure the oxidative stress and antioxidant enzymes activity spectral enzymatic analysis was used, that is material-intensive, time-consuming, and inefficient. In the present study, the four more studied and main antioxidant enzymatic assays are miniaturized in a 96-well plate system and monitored the activity of enzymes by spectrophotometry. This method has obvious advantages over the standard cuvette analysis method because the miniaturization of the 96-well microplate system decreases the amount of reaction mixture and enzymes extract, thrifts working time, and consumable costs as well.

We have unlocked the mechanistic behavior of negative capacitance in perovskite solar cells (PSCs) by analyzing impedance spectra at variable photovoltage and applied bias, temperature-dependent capacitance versus frequency ( C-f ) spectra, and current-voltage ( J-V ) characteristics. We noted that p-i-n type PSCs having PEDOT:PSS or PTAA as hole transport layer display negative capacitance feature at low and intermediate frequencies. The activation energies ( E a ) for the observance of negative capacitance were found to be in a similar order of magnitude required for the ionic migration. Moreover, the kinetic relaxation time (τ kin ) estimated to be in the same order of magnitude required to activate the halide ion migration. Our investigation suggests that the primary reason for the appearance of negative capacitance in PSCs with a p-i-n configuration is associated with the migration of halide ions and vacancies in the perovskite layers., Competing Interests: The authors declare no conflict of interest., (© 2020 The Author(s).)

Glandless cotton can be grown to obtain cotton seeds free of toxic gossypol for use as both food and feed. However, they are not grown normally due to their lesser productivity and higher susceptibility to biotic stress. Great attention has been paid to biotic stresses rather than abiotic stresses on glandless cotton. Chromium (Cr) is a common pollutant of soil and considered a serious threat to plants due to its adverse effects on different functions. Although numerous studies are available on the toxicity of Cr 6+ in various plants. However, its adverse effects and mechanism of toxicity in glandless cotton can seldom be found in the literature. This study examined the Cr 6+ effect on glandless cotton in comparison to glanded cotton. Four pairs of glanded and glandless cotton near-isogenic lines (NILs) were exposed to different doses (0, 10, 50, and 100 μM/L) of Cr 6+ for seven days, and biochemical, physiological, molecular, and ultrastructure changes were observed, which were significantly affected by Cr 6+ at high concentrations in all NILs. The effect of Cr 6+ on ionic contents shows the same trend in glanded and glandless NILs except for manganese (Mn 2+ ) that show inhibition in glandless (ZMS-12w and Coker-312w) and enhance in the glanded NIL (ZMS-17). The gene expression of superoxide dismutase (SOD) and peroxidase (POD) revealed similar trends as enzyme activities in glandless NILs. The principal component analysis (PCA) and Agglomerative hierarchical clustering (AHC) results of all NILs from morpho-physiological traits, cluster ZMS-16, and ZMS-17 into Cr 6+ sensitive group. While the glandless NILs have the potential to cope with the Cr toxicity by increasing the antioxidant enzyme activity and their gene expression. This study also revealed that Cr 6+ tolerance in cotton is genotypic and has an independent mechanism in the root that not related to low gossypol., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Developing cost-effective and rational hole transporting materials is critical for fabricating high-performance perovskite solar cells (PSCs) and to promote their commercial endeavor. We have designed and developed pyridine (core) bridging diphenylamine-substituted carbazole (arm) small molecules, named as 2,6PyDANCBZ and 3,5PyDANCBZ . The linking topology of core and arm on their photophysical, thermal, semiconducting, and photovoltaic properties were probed systematically. We found that the 2,6PyDANCBZ shows higher mobility and conductivity along with uniform film-forming ability as compared to 3,5PyDANCBZ . The PSCs fabricated with 2,6PyDANCBZ supersede the performance delivered by Spiro-OMeTAD and importantly also gave improved long-term stability. Our findings put forward small molecules based on core-arm linking topology for cost-effective hole selective layers designing.

The panchromatic light absorption and excellent charge carrier transport properties in organo lead halide perovskites allowed to achieve an unprecedented power conversion efficiency in excess of 25 % for thin film photovoltaics fabrication. To understand the underlying phenomena, various comprehensive set of optical and electrical techniques have been employed to investigate the charge carrier dynamics in such devices. In this perspective, we aim to summarize the electrical transport properties of perovskite thin films by using (i) impedance spectroscopy (IS), (ii) space charge limited current (SCLC), (iii) field-effect transistors (FETs) and (iv) time-of-flight (TOF) methods. We have deliberated various equivalent circuit used to model the perovskite solar cells by means of IS. The SCLC technique provide vital electrical parameters such as mobility, activation energy, traps density and distribution, carrier concentration, density of states, etc. The TOF technique measures mobility as a primary parameter while the FETs configuration provide a valuable insight into the in-plane charge transport in perovskites thin films. We believe that these notable understanding will provide insights into charge carrier dynamics in perovskite materials and devices., (© 2019 The Chemical Society of Japan & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Perovskite solar cells have set a new milestone in terms of efficiencies in the thin film photovoltaics category. Long-term stability of perovskite solar cells is of paramount importance but remains a challenging task. The lack of perovskite solar cells stability in real-time operating conditions erodes and impedes commercialization. Further improvements are essential with a view to delivering longer-lasting photovoltaic (PV) performances. An ideal path in this direction will be to identify novel dopants for boosting the conductivity and hole mobility of hole transport materials (HTMs), and by so doing, the usage of hygroscopic and deliquescent additive materials can be avoided. The present work demonstrates the employment of ionic liquids into a dissymmetric fluorene-dithiophene, FDT (2',7'-bis(bis(4-methoxyphenyl)amino) spiro[cyclopenta[2,1-b:3,4-b']dithiophene-4,9'-fluorene]) based HTM to understand the doping mechanisms. N -Heterocyclic hydrophobic ionic liquid, 1-butyl-3-methylpyidinium bis(trifluoromethylsulfonyl)imide (BMP y TFSI) as p-type dopant for FDT was found to increase the conductivity of FDT, to higher geometrical capacitance, to facilitate homogeneous film formation, and to enhance device stability. Our findings open up a broad range of hole-transport materials to control the degradation of the underlying water-sensitive active layer by substituting a hygroscopic element.

Background Telemedicine is an affordable use of information and communication technology (ICT) to enable long-distance patient care and health care services. While the developed world continues to take advantage of this technology, its concept remains new to Pakistan. This study aims to assess the knowledge and perceptions regarding telemedicine among health care professionals in Karachi, Pakistan. Methods  This cross-sectional study was carried out among doctors employed in the public health sector in Karachi from June 2018 to August 2018. Data were collected using a self-designed well-structured questionnaire using a five-point Likert scale, built after an extensive literature review. Statistical analysis was carried out using SPSS version 22. Categorical data were reported as frequencies and percentages. Results A total of 224 doctors, working in the Department of Internal Medicine (27.6%), Pediatrics (9.8%), Cardiology (6.6%), Gynecology (5.35%), Neurology (5.8%), and other specialties (44.6%), participated in the study. A total of 80.7 % of the doctors were aware of the definition of telemedicine. A total of 28.1% of them believed telemedicine to be effective in providing faster medical care while 23.2% thought of it as a means of reducing the white coat syndrome. A total of 42.9% believed that telemedicine disrupts the doctor-patient relationship and causes a breach of patient privacy. A total of 34.8% of the doctors favored the idea of introducing national standards for practicing telemedicine while 33.5% of doctors also agreed that providing a legal explanation of telemedicine to patients was of paramount importance. Poverty and lack of education (90.6%) was thought to be the biggest barrier to the practice of telemedicine in the developing world. Conclusions The knowledge regarding telemedicine among doctors in Karachi was found to be average. However, the perceptions about and attitude towards the introduction and implementation of this new technology were welcomed by the majority of participants with an emphasis on increasing awareness. Conferences and workshops are needed to increase knowledge about telemedicine in Pakistan., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2020, Ashfaq et al.)

Plant-derived natural products are of great interest due to their diversity in modern drug discovery. Sarcococca saligna has been used for the treatment of different diseases. The present study was aimed at isolating phytochemical constituents including Alkaloid-C (a), Dictyophlebine (b), Sarcovagine-D (c) and Saracodine (d) Holaphylline (e) from Sarcococca saligna to investigate the anticancer effect of these compounds. These compounds were evaluated for inhibition of aromatase enzyme of breast cancer in assistance by molecular docking simulations to understand molecular interaction between the enzyme and ligands. The IC 50 values of compound 1 and 5 were found 138.27 ± 0.01 µl and 12.91 ± 0.01 µl, respectively, and both were found active due to their bulky structures in comparison to the active site of aromatase enzyme. The standard drug exemestane showed potent activity in comparison with the test compounds, having IC 50 values of 0.052 ± 0.01 µl. Both compounds showed favorable electrostatic interactions with the active site of aromatase enzyme but the shape and steric bulk of the compounds was the limiting factor in their inhibitory effects. New lead compounds could be generated after extensive modifications guided by computational and experimental tools as a possible anticancer agents by targeting aromatase enzyme., (© 2019 John Wiley & Sons A/S.)

Perovskite solar cells have attracted significant attention during the current decade owing to their efficacy and photovoltaics performance, which has reached a new milestone in the thin-film category. Perovskite solar cells have witnessed a remarkable 25.2 % light-to-electricity conversion efficiency; however, the toxicity of the commonly employed Pb counterpart towards humans as well as the environment, in addition to material instability, are current bottlenecks towards commercial application. The scientific community has explored other metal ions as substitutions for Pb, while preserving the unique properties of the material, to produce environment-friendly perovskites. In this Review, we highlight the recent developments and challenges of Pb-free halide perovskite-based light harvesters for solar cell applications. This summary is intended to aid in the further development of a materials library for this sustainable technology., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Three-dimensional hybrid perovskite materials (CH 3 NH 3 PbI 3 ) suffer from intrinsic instability owing to organic cation evaporation and ion migration. The inclusion of a large organic cation such as guanidinium has been probed to stabilize the structure. This work proposes the inclusion of imidazolium iodide (C 3 N 2 H 5 I) as an organic cation inside the CH 3 NH 3 PbI 3 matrix, as a reservoir to control the spontaneous loss of iodide. The introduction of imidazolium iodide in amounts below 20 % has an impact on the crystallization process but not on the optical properties. It also positively controls non-radiative recombination and improves the open-circuit voltage of the solar cells. The present study paves way for a deeper insight into the limit of multi-dimensional perovskite to further push the performance., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

In recent years, organo-halide perovskite solar cells have garnered a surge of interest due to their high performance and low-cost fabrication processing. Owing to the multilayer architecture of perovskite solar cells, interface not only has a pivotal role to play in performance, but also influences long-term stability. Here we have employed diverse morphologies of electron selective layer (ESL) to elucidate charge extraction behavior in perovskite solar cells. The TiO₂ mesoporous structure (three-dimensional) having varied thickness, and nanocolumns (1-dimensional) with tunable length were employed. We found that a TiO₂ electron selective layer with thickness of about c.a. 100 nm, irrespective of its microstructure, was optimal for efficient charge extraction. Furthermore, by employing impedance spectroscopy at different excitation wavelengths, we studied the nature of recombination and its dependence on the charge generation profile, and results showed that, irrespective of the wavelength region, the fresh devices do not possess any preferential recombination site, and recombination process is governed by the bulk of the perovskite layer. Moreover, depending on the type of ESL, a different recombination mechanism was observed that influences the final behavior of the devices.

Perovskites solar cells are gaining interest due to their attractive solar-to-electricity conversion efficiencies; however, they suffer from certain problems, such as suboptimal ion migration and stability issues. We report here on the inclusion of a phenyloxazolium salt (2-phenyl-3-methyloxazolium iodide) in perovskite solar cells based on methyl ammonium lead triiodide (MAPbI 3 ). The fabricated solar cells not only displayed improved photovoltaic properties, but importantly the oxazolium cations can protect the perovskite layers from UV exposure as they down-convert electromagnetic irradiation; that is, the photons in the UV are absorbed and re-emitted at a different wavelength. The loading of 2-phenyl-3-methyloxazolium iodide in the perovskite precursor solution was optimized, the resulting perovskite films characterized, and the solar cells fabricated from them evaluated for their performance. Overall, this simple approach serves to optimize the performance parameters of perovskites films for solar cell applications., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Organohalide perovskites have emerged as highly promising replacements for thin-film solar cells. However, their poor stability under ambient conditions remains problematic, hindering commercial exploitation. The addition of a fluorous-functionalized imidazolium cation during the preparation of a highly stable cesium-based mixed perovskite material Cs 0.05 (MA 0.15 FA 0.85 ) 0.95 Pb(I 0.85 Br 0.15 ) 3 (MA=methylammonium; FA=formamidinium) has been shown to influence its stability. The resulting materials, which vary according to the amount of the fluorous-functionalized imidazolium cation present during fabrication, display a prolonged tolerance to atmospheric humidity (>100 days) along with power conversion efficiencies exceeding 16 %. This work provides a general route that can be implemented in a variety of perovskites and highlights a promising way to increase perovskite solar cell stability., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Triple cation based perovskite solar cells offer enhanced moisture tolerance and stability compared to mixed perovskites. Slight substitution of methyl ammonium or formamidinium cation by cesium (Cs + ), was also reported to eliminate halide segregation due to its smaller size. To elucidate the device kinetics and understand the role of the Cs, we undertook different modes of scanning probe microscopy and electrochemical impedance spectroscopy (EIS) experiments. Kelvin probe force microscopy revealed that the incorporation of the Cs cation increases the contact potential difference (CPD), this CPD further increases when Spiro-OMeTAD is used as a hole transport material. The current at the nanoscale level shows improvement with Cs inclusion and further enhancement by the Spiro-OMeTAD deposition, studied under light illumination, which supports the high photocurrent density obtained from the cells. EIS demonstrates that in a triple cation environment, reduced carrier recombination at the TiO 2 /perovskite interface was also obtained which in turn allow us to achieve a higher V oc value.

Towards increasing the stability of perovskite solar cells, the addition of Cs + is found to be a rational approach. Recently triple cation based perovskite solar cells were found to be more effective in terms of stability and efficiency. Heretofore they were unexplored, so we probed the Cs/MA/FA (cesium/methyl ammonium/formamidinium) cation based perovskites by X-ray photoelectron spectroscopy (XPS) and correlated their compositional features with their solar cell performances. The Cs + content was found to be optimum at 5%, when incorporated in the (MA 0.15 FA 0.85 )Pb(I 0.85 Br 0.15 ) 3 lattice, because the corresponding device yielded the highest fill factor compared to the perovskite without Cs + and with 10% Cs + . XPS studies distinctly reveal how Cs + aids in maintaining the expected stoichiometric ratios of I : Pb 2+ , I : N and Br : Pb 2+ in the perovskites, and how the valence band (VB) edge is dependent on the Cs + proportion, which in turn governs the open circuit voltage. Even at a low content of 5%, Cs + resides deep within the absorber layer, and ensures minimum distortion of the VB level (compared to 0% and 10% Cs + perovskites) upon Ar + sputtering, thus allowing the formation of a stable robust material that delivers excellent solar cell response. This study which brings out the role of Cs + is anticipated to be of paramount significance to further engineer the composition and improve device performances.

Perovskite solar cells with variety of hole selective contacts such as 2,2',7,7'-tetrakis(N,N-di-p-methoxyphenylamine)-9,9'-spirobifluorene (Spiro-OMeTAD), poly(3-hexylthiophene-2,5-diyl), poly[bis(4-phenyl)(2,5,6-trimentlyphenyl)amine], 5,10,15-trihexyl-3,8,13-tris(4-methoxyphenyl)-10,15-dihydro-5H-diindolo[3,2-a:3',2'-c]carbazole (HMPDI), and 2',7'-bis(bis(4-methoxyphenyl)amino)spiro[cyclopenta[2,1-b:3,4-b']dithiophene-4,9'-fluorene] were employed to elucidate its role at the interface of perovskite and metallic cathode. Microscopy images revealed Spiro-OMeTAD and HMPDI produce smoother and intimate contact between perovskite/hole transporting materials (HTM) interfaces among others evaluated here. This morphological feature appears to be connected with three fundamental facts: (1) hole injection to the HTM is much more efficient as evidenced by photoluminescence measurements, (2) recombination losses are less important as evidenced by intensity-modulated photovoltage spectroscopy and impedance spectroscopy measurements, and (3) fabricated solar cells are much more robust against degradation by moisture. Devices with higher open-circuit photovoltages are characterized by higher values of the recombination resistance extracted from the impedance data. The variation in device hysteresis behavior can be ascribed mainly due to the molecular interaction and the core of HTM employed. In all cases, this fact is related with a larger value of the low-frequency capacitance, which indicates that the HTM can induce specific slow processes of ion accumulation at the interface. Notably, these processes tend to slowly relax in time, as hysteresis is substantially reduced for aged devices.

Hysteresis is one of the most remarkable features of perovskite solar cells; however, it is also present in other kinds of devices such as dye-sensitized solar cells. Hysteresis is due to underlying slow dynamic processes that interfere with the process of charge separation which depends critically on the selective contacts used. In this work we focus on the low-frequency (0.1-10 Hz) dynamics using impedance and intensity-modulated photocurrent spectroscopy and found that both perovskite solar cells (PSCs) and "viscous electrolyte containing" dye-sensitized solar cells (DSSCs) can be described on the same fundamental grounds. By comparing different electrolyte compositions in DSSCs and both methylammonium and formamidinium-based PSCs, we find a connection between the polar nature of the cations and the low-frequency component of these solar cells. There is evidence that in both cases ion transport and specific chemical interactions with the TiO 2 surface give rise to the slow dynamics and the hysteresis. This is mainly inferred from the slope of the capacitance vs. applied voltage which shows accumulation behavior for the formulations with higher dipole moments only.

The pressure to move towards renewable energy has inspired researchers to look for ideas in photovoltaics that may lead to a major breakthrough. Recently the use of perovskites as a light harvester has lead to stunning progress. The power conversion efficiency of perovskite solar cells is now approaching parity (>22 %) with that of the established technology which took decades to reach this level of performance. The use of a hole transport material (HTM) remains indispensable in perovskite solar cells. Perovskites can conduct holes, but they are present at low levels, and for efficient charge extraction a HTM layer is a prerequisite. Herein we provide an overview of the diverse types of HTM available, from organic to inorganic, in the hope of encouraging further research and the optimization of these materials., (© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

This study explores the excitation wavelength and fluence dependence of processes occurring in formamidinium lead triiodide (FAPbI 3 ) film using time-resolved transient absorption and terahertz spectroscopies. The results indicate that second-order processes are responsible for charge carrier recombination at low fluences of the absorbed photons (below 8.4 × 10 12 ph per cm 2 ). An increase in fluence leads to the appearance and successive reduction of the time component assigned to the Auger recombination of free charge carriers (240-120 ps). Simultaneously, the bimolecular recombination time decreases from ∼1400 to ∼700 ps. Further increasing the pump fluence produces an exciton population that recombines in 6 ps. The comparison of two characteristic bleaching bands located at 480 and 775 nm provides evidence for the validity of the two valence bands model. Excitation with higher fluences results in a marked difference in the probed dynamics at these bands, reflecting the action of two excited states at the conduction band. Our results demonstrate that a single model cannot be applied in characterizing the perovskite absorber transitions at all pump fluences. These findings are relevant in understanding their operating mechanism under specific experimental conditions, which should differ for perovskite based solar cells, lasing media or photon detectors.

Lead halide based perovskite solar cells are presently the flagship among the third generation solution-processed photovoltaic technologies. The organic cation part in the perovskite plays an important role in terms of crystal structure tuning from tetragonal to trigonal or pseudocubic or vice versa depending on the organic cations used, while it also displays different microstructure. In this paper, we demonstrate the influence of the organic cation part with respect to optical properties, hysteresis behavior, and stability. This study offers a clear understanding of the perovskite properties and how they can be modulated by compositional engineering. With a rational choice, light harvesting abilities and hysteresis behavior can be controlled in these systems. The substitution of formamidinium cation by methylammonium cation allows achieving low temperature annealing and inducing stability in perovskites together with enhanced photovoltaic properties. By the use of in-situ scanning force microscopy experiments the conversion of precursors to perovskite at a particular temperature can be visualized.

The aggregation kinetics of negatively charged borate-stabilized silver nanoparticles (NPs) induced by the cationic regioregular polythiophene polyelectrolyte poly{3-[6-(1-methylimidazolium-3-yl)hexyl]thiophene-2,5-diyl bromide} (PMHT-Br) and the morphology of formed aggregates have been investigated via ultraviolet-visible light (UV-vis) spectroscopy, transmission electron microscopy (TEM), zeta (ζ) potential measurements, dynamic light scattering (DLS), and time-resolved small-angle X-ray scattering (SAXS). Two or three populations of NPs are formed within milliseconds upon mixing the components, which differ in the mean size, extent of polymer coating, and time stability. These characteristics are primarily controlled by the PMHT-Br to Ag-NPs ratio. Population of single NPs of a mean size of ∼5 nm is present in every system and is mostly stable for a long time. At low ratios, the single NPs are most probably almost free of polymer chains and the second population includes slow, but in a limited extent, growing NPs in which single NPs might be interconnected by polymer chains. At the ratios corresponding to the charge balance in the system (ca. zero ζ-potential of NPs), the NPs aggregate, forming a second population that continuously grows in size, and finally undergo sedimentation. At the high ratios, three long-time stable populations of NPs are observed, having mean sizes of ca. 5, 13, and 35 nm; all NPs should be fully coated with PMHT-Br, giving them a positively charged stabilizing shell.

We report on studies of the formamidinium lead triiodide (FAPbI3) perovskite film using time-resolved terahertz (THz) spectroscopy (TRTS) and flash photolysis to explore charge carriers generation, migration, and recombination. The TRTS results show that upon femtosecond excitation above the absorption edge, the initial high photoconductivity (∼75 cm(2) V(-1) s(-1)) remains constant at least up to 8 ns, which corresponds to a diffusion length of 25 μm. Pumping below the absorption edge results in a mobility of 40 cm(2) V(-1) s(-1) suggesting lower mobility of charge carriers located at the bottom of the conduction band or shallow sub-bandgap states. Furthermore, analysis of the THz kinetics reveals rising components of <1 and 20 ps, reflecting dissociation of excitons having different binding energies. Flash photolysis experiments indicate that trapped charge carriers persist for milliseconds.

Four center symmetrical star-shaped hole transporting materials (HTMs) comprising planar triazatruxene core and electron-rich methoxy-engineered side arms have been synthesized and successfully employed in (FAPbI3)0.85(MAPbBr3)0.15 perovskite solar cells. These HTMs are obtained from relatively cheap starting materials by adopting facile preparation procedure, without using expensive and complicated purification techniques. Developed compounds have suitable highest occupied molecular orbitals (HOMO) with respect to the valence band level of the perovskite, and time-resolved photoluminescence indicates that hole injection from the valence band of perovskite into the HOMO of triazatruxene-based HTMs is relatively more efficient as compared to that of well-studied spiro-OMeTAD. Remarkable power conversion efficiency over 18% was achieved using 5,10,15-trihexyl-3,8,13-tris(4-methoxyphenyl)-10,15-dihydro-5H-diindolo[3,2-a:3',2'-c]carbazole (KR131) with compositive perovskite absorber. This result demonstrates triazatruxene-based compounds as a new class of HTM for the fabrication of highly efficient perovskite solar cells.

The electron dynamics of solar cells with mesoporous TiO2 contact is studied by electrochemical small-perturbation techniques. The study involved dye solar cells (DSC), solid-state perovskite solar cells (SSPSC), and devices where the perovskite acts as sensitizer in a liquid-junction device. Using a transport-recombination continuity equation we found that mid-frequency time constants are proper lifetimes that determine the current-voltage curve. This is not the case for the SSPSC, where a lifetime of ∼1 μs, 1 order of magnitude longer, is required to reproduce the current-voltage curve. This mismatch is attributed to the dielectric response on the mid-frequency component. Correcting for this effect, lifetimes lie on a common exponential trend with respect to open-circuit voltage. Electron transport times share a common trend line too. This universal behavior of lifetimes and transport times suggests that the main difference between the cells is the power to populate the mesoporous TiO2 contact with electrons.

It is not often that the scientific community is blessed with a material, which brings enormous hopes and receives special attention. When it does, it expands at a rapid pace and its every dimension creates curiosity. One such material is perovskite, which has triggered the development of new device architectures in energy conversion. Perovskites are of great interest in photovoltaic devices due to their panchromatic light absorption and ambipolar behavior. Power conversion efficiencies have been doubled in less than a year and over 15% is being now measured in labs. Every digit increment in efficiency is being celebrated widely in the scientific community and is being discussed in industry. Here we provide a summary on the use of perovskite for inexpensive solar cells fabrication. It will not be unrealistic to speculate that one day perovskite-based solar cells can match the capability and capacity of existing technologies., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Amphotericin B (AmB) lipid nanoemulsions were prepared and characterized and their suitability for pulmonary delivery via nebulization was evaluated. AmB nanoemulsions were prepared by sonicating and vortexing the drug with two commercially available lipid nanoemulsions: the Intralipid(®) or Clinoleic(®). Loading the nanoemulsions with the drug slightly increased the size of the lipid droplets and did not affect the zeta potential of the nanoemulsions. The loading efficiency of AmB was found to be 87.46±2.21% in the Intralipid(®) nanoemulsions and 80.7±0.70% in the Clinoleic(®) formulation. This respectively corresponded to 21.86 mg and 20.19 mg of AmB being successfully loaded in the nanoemulsions. On aerosolization using a Pari Sprint jet nebulizer, both nanoemulsions produced very high drug output which was approximately 90% for both formulations. Using the two-stage impinger, the Clinoleic(®) emulsion had higher fine particle fraction (FPF) than the Intralipid(®), since the Clinoleic(®) displayed higher deposition of AmB in the lower impinger stage (exceeding 80%), compared to 57% for the Intralipid(®). Overall, the ease of preparation of the AmB lipid nanoemulsions, along with their in vitro nebulization performance suggest that lipid nanoemulsions could be successful nanocarriers for delivery of AmB to the peripheral respiratory airways., (Copyright © 2012 Elsevier B.V. All rights reserved.)

We report tuning of structure dependent optical properties of colloidal systems of borate-stabilized silver nanoparticles (Ag NPs) and polythiophene-based cationic polyelectrolyte with ionic-liquid like side groups: poly{3-[6-(1-methylimidazolium-3-yl)hexyl]thiophene-2,5-diyl bromide} (PMHT-Br) towards obtaining local electromagnetic field enhancement effects. Surface-enhanced Raman scattering (SERS) studies showed that the strong electromagnetic field enhancement is related to the formation of aggregates of Ag NPs achieved at the components ratio providing the charge balance between Ag NPs and cationic polythiophene, at which Ag NPs are nearly single-polymer-layer coated, their zeta potential is close to zero and they easily form aggregates in which the mean inter-particle distance enables the occurrence of desired plasmonic effects. Fluorescence quenching is efficient only in the systems with low concentrations of PMHT-Br, in which almost all polymer chains directly interact with the Ag NPs surface., (Copyright © 2010 Elsevier Inc. All rights reserved.)